<html>
<head>
<title>Loading加载样式</title>
<style>
    body {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background-color: #fff;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        z-index: 1000;
    }
    
    div.logo {
    width: 100px;
    height: 100px;
    box-sizing: border-box;
    position: relative;
    }
 
    div.logo::before,
    div.logo::after {
        z-index: 1;
        box-sizing: border-box;
        content: '';
        position: absolute;
        border: 4px solid transparent;
        width: 0;
        height: 0;
        animation-direction: alternate;
        animation-timing-function: linear;
    }
 
    div.logo::before {
        top: 0;
        left: 0;
        animation: border-before 1.5s infinite;
        animation-direction: alternate;
    }
 
    div.logo::after {
        bottom: 0;
        right: 0;
        animation: border-after 1.5s infinite;
        animation-direction: alternate;
    }
 
    div.logo>div {
        position: absolute;
        opacity: 0;
    }
 
    div.logo div.white {
        border-left: 4px solid black;
        top: 0;
        bottom: 0;
        right: 0;
        width: 0;
        animation: white 1.5s infinite;
        animation-direction: alternate;
    }
 
    div.logo div.orange {
        border-top: 4px solid black;
        left: 0;
        bottom: 0;
        right: 0;
        height: 0;
        background-color: #F3B93F;
        animation: orange 1.5s infinite;
        animation-direction: alternate;
    }
 
    div.logo div.red {
        border-right: 4px solid black;
        top: 0;
        bottom: 0;
        left: 0;
        width: 0;
        background-color: #EA5664;
        animation: red 1.5s infinite;
        animation-direction: alternate;
    }
 
    @keyframes border-before {
        0% {
            width: 0;
            height: 0;
            border-top-color: black;
            border-right-color: transparent;
        }
        12.49% {
            border-right-color: transparent;
        }
        12.5% {
            height: 0;
            width: 100%;
            border-top-color: black;
            border-right-color: black;
        }
        25%,
        100% {
            width: 100%;
            height: 100%;
            border-top-color: black;
            border-right-color: black;
        }
    }
 
    @keyframes border-after {
        0%,
        24.99% {
            width: 0;
            height: 0;
            border-left-color: transparent;
            border-bottom-color: transparent;
        }
        25% {
            width: 0;
            height: 0;
            border-left-color: transparent;
            border-bottom-color: black;
        }
        37.49% {
            border-left-color: transparent;
            border-bottom-color: black;
        }
        37.5% {
            height: 0;
            width: 100%;
            border-left-color: black;
            border-bottom-color: black;
        }
        50%,
        100% {
            width: 100%;
            height: 100%;
            border-left-color: black;
            border-bottom-color: black;
        }
    }
 
    @keyframes red {
        0%,
        50% {
            width: 0;
            opacity: 0;
        }
        50.01% {
            opacity: 1;
        }
        65%,
        100% {
            opacity: 1;
            width: 27%;
        }
    }
 
    @keyframes orange {
        0%,
        65% {
            height: 0;
            opacity: 0;
        }
        65.01% {
            opacity: 1;
        }
        80%,
        100% {
            opacity: 1;
            height: 50%;
        }
    }
 
    @keyframes white {
        0%,
        75% {
            width: 0;
            opacity: 0;
        }
        75.01% {
            opacity: 1;
        }
        90%,
        100% {
            opacity: 1;
            width: 23%;
        }
    }
</style>
</head>
<body>
    <div class="logo">
      <div class="white"></div>
      <div class="orange"></div>
      <div class="red"></div>
    </div>
<body>
</html>